Suction cleaning tool



Nov. 16, 1965 R. M. EVANS, JR., ETAL 3,217,352

SUCTION CLEANING TOOL 5 Sheets-Sheet 1 Filed March 26, 1964 k M T 5W m m w r v r I mi? 5 Mm 2 m NOV. 1955 R. M. EVANS, JR, ETAL 3,217,352

SUCTION CLEANING TOOL 5 Sheets-Sheet 3 Filed March 26, 1964 INVENTORSI 5:55 M Era/7s Mk fiahk/m P Ha ba //Z 7776/ HTIWRNFY.

United States Patent a corporation of New York Filed Mar. 26, 1964, Ser. No. 354,850 8 Claims. (Cl. 15-328) This invention relates to a cleaning tool for use with a vacuum cleaner. More specifically, it relates to the construction of a cleaning tool comprising a portion for cleaning rugs or carpets and a portion for cleaning bare floors.

The improved cleaning tool of this invention may be used either in the main body of a vacuum cleaner, for example, in a conventional upright type vacuum cleaner, or in a separate detachable vacuum cleaner attachment, for example, one for use with a canister type vacuum cleaner.

The cleaning tool of this invention comprises a rug cleaning tool useful in cleaning rugs, carpets, and other equivalent floor coverings. To clean rugs, two types of foreign material must be removed from the rug. A straight suction must be provided for removing granular particles, and a second type cleaning action, for which brushes are commonly used in combination with a vacuum, for removing lint, strings and the like from the rug tufts. Prior art rug cleaning tools have not met with complete success, some of the disadvantages being the collection of lint on the brushes, which must be manually removed by the operator, and difficulty in balancing the effectiveness of the brushes and the mobility of the rug cleaning tool. The latter mentioned difficulty arises because the most effective brush action occurs as the brush bristles engage the rug with increased force, but this increased force causes greater difiiculty in moving the rug cleaning tool over the rug. The mobility of prior art rug cleaning tools has also been limited by the sealing of the tool to the rug. This scaling is caused by drawing the cleaning air between the base of the tool and the rug.

In accordance with this invention, an improved cleaning tool is provided, which includes a rug cleaning tool in which an optimum balance is provided between the ease of movement of the rug cleaning tool, and the lint gathering effectiveness of the brushes. Cleaning air is drawn into the tool from the top, thereby eliminating sealing of the tool to the rug. Furthermore, in accordance with this invention, the cleaning tool includes a bare floor cleaning attachment which is easily incorporated in the rug cleaning tool, thereby eliminating the need for a separate bare floor tool including its connecting means.

It is an object of this invention to provide a versatile vacuum cleaning tool usable on rugs and on bare floors.

It is an object of this invention to provide a rug cleaning tool which will remove lint, strings, etc. from a rug, and in which the brushes used for removing the lint, strings, etc. from the rug are self-cleaning.

It is an object of this invention to provide a rug cleaning tool which is fully effective in cleaning all types of material from a rug, without any sacrifice in the ease of movement of the cleaning tool over the rug.

It is another object of this invention to provide the vacuum cleaning tool with a bare floor cleaning attachment which may be easily incorporated in the rug cleaning tool, whereby the bare floor cleaning function may be provided conveniently and at a minimum expense.

These objects are accomplished in accordance with this invention, in one form thereof, by providing a vacuum cleaning tool including a rug cleaning tool, and a bare floor cleaning attachment. The housing of the cleaning tool is molded from a single piece of plastic, with a rec- 3,217,352 Patented Nov. 16, 1965 "ice tangular opening provided in the bottom, to which a vacuum is applied. A pair of brushes lie along the longer edges of the opening, and together with the applied vacuum provide the desired complete cleaning of a rug. The bottom of the tool is provided with a sole plate which extends over the sides of the brushes to provide a smooth surface to support the rug cleaning tool on a rug. Cleaning air is drawn into the tool from the top to eliminate sealing of the sole plate and the rug. The vacuum cleaning tool is also provided with a bare floor cleaning attachment which comprises a plastic housing having brush bristles projecting from one side thereof, and upstanding members from the opposite side thereof, for attachment to the rug cleaning tool. The attachment engages the rug tool in such a manner as to block the flow of air into the vacuum cleaning tool except through the attachment.

Further objects and advantages of my invention as well as other modifications and uses thereof will become apparent as the description proceeds. My invention will be better understood by reference to the accompanying drawings in which:

FIG. 1 is a top plan view, with portions broken away, of a rug cleaning tool which incorporates the improved construction contemplated by this invention;

FIG. 2 is a bottom plan view thereof, with some portions removed and others broken away for the sake of clarity;

FIG. 3 is a sectional view taken substantially on line 3-3 of FIG. 1, with the rug cleaning tool engaging a rug.

FIG. 4 is a sectional view taken substantially on line 44 of FIG. 1, with the rug cleaning tool engaging a rug.

FIG. 5 is a sectional view taken substantially on line 55 of FIG. 1 with the bare floor cleaning attachment, partially broken away, shown in proper relationship with the rug cleaning tool for attachment thereto.

FIG. 6 is an exploded view of the brush retaining clamp of the improved rug cleaning tool contemplated by this invention.

FIG. 7 is a sectional elevation view of the cleaning tool with the bare floor cleaning attachment inserted in the rug cleaning tool.

FIG. 8 is a perspective view of the improved bare floor cleaning attachment contemplated by this invention.

By reference to FIGS. 1 through 6 of the drawings, it will be seen that in the preferred embodiment of this invention a generally rectangular housing 10 is molded from a single piece of plastic. Molded in the housing is a top chamber 11, which is co-extensive with the periphery of the housing excepting only the upstanding portion 12, under which is clamped an outlet 14 by an outlet retaining member 13.

Three chambers, a front chamber 15, a middle chamber 16, and a back chamber 17 are formed in the bottom of housing 10. Outlet 14 is connected to the middle chamber 16. A pair of vertical walls 18, which form the sides of middle chamber 16, and a pair of inclined walls 19 and 20, which form portions of the front chamber 15 and the back chamber 17 respectively, terminate in a pair of lips 21 which are the lowermost portion of the housing 10.

A front brush 22 and a back brush 23 are mounted in the front and rear chambers abutting inclined walls 19 and 20 respectively. The brushes are resiliently biased with respect to the housing in the direction of the brush bristles by a pair of leaf springs 24. The resilient bias causes the brushes to engage the rug being cleaned with a substantially constant force irrespective of brush wear or 111g type. A pair of brush retaining members 25, one of which is best shown in FIG. 6, engage the opposite ends of the brushes, and aid in holding the brushes within the housing. The brushes are retained in the housing against the action of the leaf springs 24 by the tabs 26 of the brush retaining members. The arms 27 of the brush retaining members 25 hold the brushes against the inclined walls 19 and 20. An offset flat portion 28 of the brush retaining members 25 engages a wall 29 of the housing, thereby aligning the retaining member within the housing 10. The brush retaining members 25 are held in the housing by a sole plate 30, which extends over the ends 31 of the brush retaining members.

It will be noted that back brush 23 and the inclined wall 20 are inclined to the sole plate at a lesser angle than the front brush 22 and inclined wall 10. During use of the rug cleaning tool, the operator will push the nozzle for ward with the sole plate resting squarely on the rug, but during the return stroke the operator tends to lift the back of the tool, by pulling up on the outlet 14. In order to have the front brush 22 contact the rug tufts 38 at a predetermined preferred operating angle during the return stroke, the wall 19 is inclined to the sole plate at a greater angle than the predetermined preferred operating angle. Thus, when the back of the cleaning tool is lifted during the return stroke and the housing is tilted forward, the front brush 22 is brought into the preferred angular relationship with the sole plate 30, and therefore the carpet tufts 38. The operator when pushing the nozzle forward will tend to keep the large fiat portion 37 of the sole plate in contact with the rug, and therefore the back brush 23 is mounted at the predetermined preferred operating angle. The tips 40 of the bristles of the front and back brushes are cut at an angle, such that the tips of the brushes are parallel to the surface to be cleaned during use of the rug cleaning tool.

The sole plate 30, in addition to holding the brush retaining members 25 in the housing, serves as a support for the rug cleaning tool and encloses the front and back chambers. by the engagement of the front edge 32 of the sole plate in the notches 33 provided in the housing, and by a U- shaped resilient clamp 34 which engages a portion of the outlet retaining member 13. The sole plate is provided with a rectangular opening 35, which is in alignment with the middle chamber 16, and which exposes the tips of the brushes 22 and 23. A narrow front portion 36 of the sole plate encloses the front chamber 15, and a large flat portion 37 encloses the back chamber 17.

During the forward cleaning stroke, the rug cleaning tool is supported on the tufts 38 of rug 39, primarily by the large flat portion 37 of the sole plate 30. During a return stroke an operator tends to lift the rear of the tool, thereby causing the rug cleaning tool to be supported primarily by the narrow front portion 36. The tips of the front and back brushes 22 and 23 respectively are biased into engagement with the rug tufts 38 by the leaf.

springs 24. It should be noted with reference to FIGS. 3 and 4, that the lips 21 are spaced from the tufts 38 of the rug 39 when the sole plate 30 and the tips 40 of the brushes are in engagement with the tufts 38 of the rug 39. This space is provided so that air may flow from the front and back chambers over the brushes and the rug to be cleaned into the middle chamber.

In order to provide air flow from the top of the housing, rather than between the supporting surface and the rug, passageways 41 are provided in the housing 10 between the top chamber 11, and the front chamber 15. Similarly, passageways 42 are provided in the housing 10 between the top chamber 11 and the back chamber 17. When. a suction source is applied to outlet 14, air is drawn into the top chamber 11, through passageways 41 and 42 into the front and back chambers respectively, over the front and back brushes 22 and 23 respectively in the direction of the brush bristles, under the lips 21 into the middle chamber 16, and thereafter to the suction outlet 14.

A cover 43 is mounted on top of the housing 10, so as to partially enclose the top chamber 11. The cover is spaced from the front and back top surfaces of the hous- The sole plate 39 is attached to the housing ing 10 to form air passageway 44 at the front of the housing, and air passageway 45 at the back of the housing. The cover 43 is maintained in the spaced relationship from the top surfaces of the housing 10 to provide these passageways by engagement between spacing members 46 carried on the cover and the outer top wall 47 and the outer side walls 48 of the middle chamber 16.

The pressure differential between the middle chamber 16 and the atmosphere is regulated by a pair of vacuum control valves 49 which are mounted in the middle chamber 16 to control the flow of air between the middle chamber 16 and the top chamber 11 through passageways 50 formed in the housing between the middle chamber and the top chamber. Each of the vacuum control valves 49 comprises a resilient metal lever arm 51 and a resilient pad 52 glued to the lever arm. The lever arm is attached to the housing by fastening member 53, which also secure cover 43 to the housing.

In order to clean hard surfaces, such as bare floors, the improved vacuum cleaning tool includes an attachment 54, the preferred embodiment of which is shown in FIGS. 5, 7, and 8. The attachment includes a main body 55 which is formed from a single piece of plastic to include a central chamber 56, a substantially flat upper surface 57, and an upstanding member 58 surrounded by a shoulder 59, which is slightly higher than the upper surface. The upstanding member 58 is provided with a pair of U-shaped springs 60 which engage the vertical walls 18 of the middle chamber 16 when the attachment is inserted in the rug cleaning tool as shown in FIG. 7. Referring again to FIG. 7, it will be noted that when the upstanding member 58 is inserted in the middle chamber 16 of the housing, the substantially flat upper surface 57 of the attachment engages the tips 40 of the brushes and the shoulder 59 engages the lips 21, thereby causing the air to flow from the central chamber 56 of the attachment through a passageway 61 between the central chamber 56 and the top of the main body, through the middle chamber 16 to the outlet 14. The lower surface of the main body 55 is provided with holes, in which are mounted brush bristles 62. The bristles 62 are spaced around the central chamber 56, so that when the brush bristles 62 engage a bare floor 63, as shown in FIG. 7, the dirt will be loosened from the floor by the bristles, and drawn up through the central chamber 56 through the passageway 61 into the middle chamber 16 and thereafter to the outer 14.

The improved operation of the rug cleaning tool can best be described by reference to FIGS. 3 and 4. With the rug cleaning tool resting on a rug, vacuum source is connected to the outlet 14, whereby a suction is applied through the middle chamber 16 to the tufts 38 of the rug 39 in the area immediately under the middle chamber 16. The narrow front portion 36 and the large flat portion 37 of the sole plate rest on the tufts 38 of the rug 39, thereby inhibiting the flow of air between the sole plate and the tufts. Air is drawn under the cover 43 through air passageways 44 and 45 into the back chamber 17 through the passageways 42, and into the front chamber 15 through passageways 41. The air is then drawn over the brushes 22 and 23 in the direction of the brush bristles and under the lips 21 into the middle chamber 16. The air flow over the brushes in the direction of the bristles tends to clean the brushes, thereby providing self-cleaning, as opposed to the prior art where it was necessary to clean the bristles by hand after use of a rug cleaning tool.

When it is desirable to clean bare floors the bare floor cleaning attachment 54 is secured tothe rug cleaning tool. A vacuum applied to the nozzle outlet 14 will cause air to flow through the bristles 62 into the central chamber 56, through the passageway 61 into the middle chamber 16 of the housing. The engagement of the shoulder 59 of the attachment with the lips 21 and the upper surface 57 with the brush tips 40 restricts the flow of air through. the front and back chambers, whereby the air flowing into the middle chamber is drawn through the brush bristles 62 into the central chamber 56 and then through passageway 61. While a preferred embodiment of the invention has been shown, various other modifications and embodiments of the invention will be apparent to those skilled in the art, and it is intended to cover by the appended claims all said modifications falling within the scope thereof.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A cleaning tool adapted for use with a suction-type cleaner, including a rug cleaning tool comprising a generally rectangular housing having formed therein at least one chamber in the top of said housing and a plurality of chambers in the bottom of said housing, the bottom chambers including a middle chamber and front and back chambers formed on opposite sides of said middle chamber, a vacuum outlet communicating with said middle chamber, the vacuum outlet being adapted to be connected to a vacuum source, said middle chamber having side walls terminating in a pair of lips, a pair of brushes, one

mounted in each of said front and back chambers, brush mounting means to bias said brushes into engagement with the surface to be cleaned, said brushes being inclined so as to converge toward said middle chamber, a sole plate partially covering said front and back chambers, means for attaching said sole plate to said housing, said housing including passageways between said front and back chambers and said top chamber for providing air flow between said top and said front and back chambers, over said brushes in the direction of said brush bristles so as to clean said brushes and over said lips into said middle chamber, said cleaning tool including an attachment useful for cleaning hard surfaces, said attachment 'being secured in said middle chamber by means engaging the side walls of said middle chamber, said attachment having an upper surface which engages the tips of said brushes and said lips to cut off the air flow over said brushes in said front and back chambers, said attachment having a central chamber, a strip brush at least partially surrounding said central chamber, said attachment having a passageway therein between said central chamber and said middle-chamber.

2. A cleaning tool for use with a suction-type cleaner, adapted for use in the cleaning of rugs and the like, comprising a generally rectangular housing having formed therein at least one chamber in the top of said housing and a plurality of chambers in the bottom of said housing, the bottom chambers including a middle chamber and front and back chambers formed on opposite sides of said middle chamber, a nozzle outlet communicating with said middle chamber, the nozzle outlet being adapted to be connected to a vacuum source, said middle chamber having side walls terminating in a pair of lips, a pair of brushes, one mounted in each of said front and back chambers, brush mounting means to bias said brushes into engagement with the surface to be cleaned, said brushes being inclined so as to converge toward said middle chamber, said brush in said back chamber being mounted at a predetermined angle to the surface to be cleaned, said brush in said front chamber being mounted at a greater angle to the surface to be cleaned than said predetermined angle, so that as said cleaning tool is lifted during a return clean-ing stroke, said brush is inclined to the surface at said predetermined angle, a sole plate covering said front and back chambers, means for attaching said sole plate partially to said housing, said housing including passageways between said front and back chambers and said top chamber for providing air flow between said top and said front and back chambers, over said brushes in the direction of said brush bristles so as to clean said brushes and over said lips into said middle chamber.

3. A cleaning tool as recited in claim 2 wherein said sole plate covers the sides of said inclined brushes so that only the tips of the brush bristles engage the surface to be cleaned, said sole plate having an opening adjacent said middle chamber, and said sole plate having a large flat portion extending behind said opening to serve as a skid to support said nozzle while in use.

4. A cleaning tool for use with a suction-type cleaner, adapted for use in the cleaning of rugs and the like, comprising a generally elongated housing, an imperforate cover mounted on and spaced above said housing for cooperating with the top portion of said housing to define a top chamber, a plurality of chambers formed in the bottom of said housing, the bottom chambers including a middle chamber and front and back chambers formed on opposite sides of said middle chamber, a nozzle outlet communicating with said middle chamber, the nozzle outlet being adapted to be connected to a vacuum source, said middle chamber having side walls terminating in a pair of lips, a pair of brushes, one mounted in each of said front and back chambers, brush mounting means to bias said brushes into engagement with the surface to be cleaned, said brushes being inclined so as to converge toward said middle chamber, a sole plate partially covering said front and back chambers, means for attaching said sole plate to said housing, said housing including passageways between said front and back chambers and said top chamber, said cover extending directly over inlets to said passageways so that when a suction is applied to said middle chamber, air is drawn under said cover into said top chamber, through said passageways between said top and said front and back chambers, over said brushes in the direction of said brush bristles so as to clean said brushes and over said lips into said middle chamber.

5. A cleaning tool as recited in claim 4 wherein said housing is provided with additional passageways between said middle chamber and said top chamber, and valve means mounted over said passageways to limit the pressure drop in said middle chamber.

6. A cleaning tool adapted for use with a suction-type cleaner, including a rug cleaning tool, comprising a generally rectangular housing having formed therein at least one chamber in the top of said housing and a plurality of chambers in the bottom of said housing, the

bottom chambers including a middle chamber and front and back chambers formed on opposite sides of said middle chamber, a nozzle outlet communicating with said middle chamber, the nozzle outlet being adapted to be connected to a vacuum source, said middle chamber having side walls terminating in a pair of lips, a pair of brushes, one mounted in each of said front and back chambers, brush mounting means to bias said brushes into engagement with the surface to be cleaned, said brushes being inclined so as to converge toward said middle chamber, a sole plate partially covering said front and back chambers, means for attaching said sole plate to said housing, said cleaning tool including an attachment useful for cleaning hard surfaces, said attachment secured in said middle chamber by means engaging the side walls of said middle chamber, said attachment having an upper surface which engages said brushes and said lips, said attachment having a central chamber, a strip brush at least partially surrounding said central chamber, said attachment having a passageway therein between said central chamber and said middle chamber.

7. A cleaning tool adapted for use with a suction-type cleaner, including a rug cleaning tool, comprising a generally rectangular housing having formed therein at least one chamber in the top of said housing and a plurality of chambers in the bottom of said housing, the bottom chambers including a middle chamber and front and back chambers formed on opposite sides of said middle chamber, a nozzle outlet communicating with said middle chamber, the nozzle outlet being adapted to be connected to a vacuum source, said middle chamber having side walls terminating in a pair of lips, a pair of brushes, one mounted in each of said front and back chambers, brush mounting means to bias said brushes into engagement with the surface to be cleaned, said brushes being include so as to converge toward said middle chamber, a sole plate partially. coveringsaid front and back chambers, means for attaching said sole plate to saidhousing, said housing including passageways between said front and back chambers and said top chamber for providing air flow between said top and said front and back chambers, over said brushes in the direction of said brush bristles so as to clean said brushes and over said lips into said middle chamber, said cleaning tool including an attachment useful for cleaning hard surfaces, said attachment having an upper surface from which projects an upstanding member, said'upstanding member having a shape generally conforming to that of said middle chamber, a pair of U-shaped compression springs mounted on said upstanding member, said upstanding member being insertable within said middle chamber and said U shaped compression springs engaging the side walls of said middle chamber to secure said attachment in said middle chamber, said upper surface of said attachment engaging said brushes and said lips to'cut off the air flow over said brushes, said attachment having a central chamber, a strip brush at least partially surrounding saidcentral chamber, said attachment having a passageway therein between said central chamber and said middle chamber.

8. A cleaning tool for use with a suction-type cleaner, adapted for use in the cleaning of rugs and the like, comprising a generally rectangular housing, having formed therein at least one chamberin the topof said housing, a cover mounted oversaid top chamberand spaced from said housing, a plurality of chambers formed in'the bottom of said housing, the, bottom chambers including a middle chamber and front and back chambers formed on opposite sides ofsaid middle chamber, a nozzle outlet communicating with said middle :chamber, the nozzle outlet being adapted to be connected to a vacuum source, said middle chamber having side walls terminating in a pair of lips, a pair of brushes, one

mounted in each of said front and back chambers, brush mounting means to bias said brushes into engagement with the surface to be cleaned, said brushes being inclined so as to converge toward said middlechamber,

said brush in said back chamber being mounted at a predetermined angle to the surface to be cleaned, said brush in said frontchamber being mounted ata greater angle to the surface to be cleaned than the predetermined angle, so that as said nozzle is lifted during a return cleaning stroke, said brush is inclined to a surface at said predeterminedtangle, a sole plate partially covering said front and back chambers and having an opening in alignment with said middle chamber, means for attachingtsaid sole plate to said housing, said sole plate covering the sides of said inclined brushes, so that only the tips of'the brush bristles can engage the surface to be cleaned, saidtsole plate having a. large flat portion extending behind said opening in said sole plate to serve as a skid to support said nozzle .while in use, said housing including passageways between said front and back chambers and said top chamber, so that when a suction is applied to said middle chamber, air is .drawn under said cover into said top chamber, through said passageways between said top and said front and back chambers, over said brushesin the direction of said brush bristles so as to clean said brushes and over said lips into said middle chamber, said housing beingprovided with additional passageways between said middle chamber and said top chamber, and valve means mounted over said passageways to limit the pressure drop in said middlechamber.

References Cited by theExaminer UNITED STATES PATENTS 2,153,457 4/1939 Fechtenburg 15 368 2,703,903 3/1955 Faith-Ell 15-400 vX 2,862,225 12/1958 Stevens 15365 2,950,497 8/1960 Smith 15371 X 2,972,771 2/1961 Kemper 15400 X 3,002,217 10/1961 Smithson et. al. 15371 X FOREIGN PATENTS 1,058,712 6/ 1959 Germany. 1,093 ,963 12/ 1960 Germany.

875.332 8/1961 Great Britain.

WALTER A. SCHELL, Primary Examiner. 

1. A CLEANING TOOL ADAPTED FOR USE WITH A SUCTION-TYPE CLEANER, INCLUDING A RUG CLEANING TOOL COMPRISING A GENERALLY RECTANGULAR HOUSING HAVING FORMED THEREIN AT LEAST ONE CHAMBER IN THE TOP OF SAID HOUSING AND A PLURALITY OF CHAMBERS IN THE BOTTOM OF SAID HOUSING, THE BOTTOM CHAMBERS INCLUDING A MIDDLE CHAMBER AND FRONT AND BACK CHAMBERS FORMED ON OPPOSITE SIDES OF SAID MIDDLE CHAMBER, A VACUUM OUTLET COMMUNICATING WITH SAID MIDDLE CHAMBER, THE VACUUM OUTLET BEING ADAPTED TO BE CONNECTED TO A VACUUM SOURCE, SAID MIDDLE CHAMBER HAVING SIDE WALLS TERMINATING IN A PAIR OF LIPS, A PAIR OF BRUSHES, ONE MOUNTED IN EACH OF SAID FRONT AND BACK CHAMBERS, BRUSH MOUNTING MEANS TO BIAS SAID BRUSHES INTO ENGAGEMENT WITH THE SURFACE TO BE CLEANED, SAID BRUSHES BEING INCLINED SO AS TO CONVERGE TOWARD SAID MIDDLE CHAMBER, A SOLE PLATE PARTIALLY COVERING SAID FRONT AND BACK CHAMBERS, MEANS FOR ATTACHING SAID SOLE PLATE TO SAID HOUSING, SAID HOUSING INCLUDING PASSAGEWAYS BETWEEN SAID FRONT AND BACK CHAMBERS AND SAID TOP CHAMBER FOR PROVIDING AIR FLOW BETWEEN SAID TOP AND SAID FRONT AND BACK CHAMBERS, OVER SAID BRUSHES IN THE DIRECTION OF SAID BRUSH BRISTLES SO AS TO CLEAN SAID BRUSHES AND OVER SAID LIPS INTO SAID MIDDLE CHAMBER, SAID CLEANING TOOL INCLUDING AN ATTACHMENT USEFUL FOR CLEANING HARD SURFACES, SAID ATTACHMENT BEING SECURED IN SAID MIDDLE CHAMBER BY MEANS ENGAGING THE SIDE WALLS OF SAID MIDDLE CHAMBER, SAID ATTACHMENT HAVING AN UPPER SURFACE WITH ENGAGES THE TIPS OF SAID BRUSHES AND SAID LIPS TO CUT OFF THE AIR FLOW OVER SAID BRUSHES IN SAID FRONT AND BACK CHAMBERS, SAID ATTACHMENT HAVING A CENTRAL CHAMBER, A STRIP BRUSH AT LEAST PARTIALLY SURROUNDING SAID CENTRAL CHAMBER, SAID ATTACHMENT HAVING A PASSAGEWAY THEREIN BETWEEN SAID CENTRAL CHAMBER AND SAID MIDDLE CHAMBER. 